Page 202 - New Medley 5 Semester 2

Competencies
C-4.5, C-6.1

• Critical Thinking
• Analysing
• Experiential Learning
• Hands-on Learning
21st CENTURY SKILLS • Remembering
1 Wonders of Air • Creativity
• Problem Solving
• Communication

Warm Up • Critical Thinking

Air and water are two basic
necessities of life. Air is
everywhere. Can you tell how

the size of balloon grows
bigger on blowing it?

AIR AROUND US

Have you ever seen air? We cannot see air, but we can feel it when it blows.

Moving air is called wind. Air is present all around us. e thick layer of air
around the earth is called atmosphere. e atmosphere extends up to a height

of about 800 kilometres above the surface of earth.

Composition of Air

Air is a mixture of many gases. It contains 78 per cent

nitrogen, 21 per cent oxygen, 0.03 per cent carbon
dioxide, some water vapour and other gases. 78% nitrogen

All living things breathe in air to get oxygen from

it. is oxygen is taken by the blood and given to 21% oxygen
di erent parts of the body to perform life activities.

Carbon dioxide is given out as a result of respiration. 1% other gases

Oxygen also supports burning of re. Composition of air

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